Gas turbine power plant utilizing solid water-bearing fuel



May 4, 1954 R. G. voYsl-:Y 2,677,237

GAS TURBINE POWER PLANT UTILIZING SOLID WATER-BEARING FUEL Filed Sept. l0, 1951 Patented May 4, 1954 GAS TURBINE POWER PLANT UTILIZING SOLID WATER-BEARING FUEL Reginald G. Voysey, Walton-on-Thames, England, assignor to Power Jets `(Research and Development) Limited, London, England, a Britl ish company Application September 19, 1951, Serial No. 245,941

Claims priority, application Great Britain September 14, 1950 2 Claims.

This invention relatesv to gas turbine power plants utilising solid water-bearing fuel, and is an improvement or modification of the constructions described in lso-pending United States Patent application Serial No. 103,993, filed July 11, 1949 in the name of Campbell H. Secord.

By the term water-bearing fuel herein is meant a fuel containing or being otherwise combined with a substantial quantity of water which might amount to as much as ten times its own weight. Such a fuel may for example be bagasse, sewage sludge, coal slurry, sulphite pulp mill waste, town refuse or peat.

As more fully'explained in said co-pending application, this type of gas turbine combines the idea of injecting water into the working fluid system with the use of a fuel having a water content such as to render its use normally uneconomic. The use of water injection has the result that, for a designed temperature at the turbine, the quantity of cooling air above that required for complete combustion may be reduced and the size of the plant correspondingly decreased. Such water injection normally requires a large external supply of water but this is obviated in the present case by utilising the water of a water-bearing fuel which might otherwise be useless. This introduction of water will be particularly advantageous if the quantity of water supplied to the working fluid system reaches a maximum amount consistent with a designed maximum temperature at the turbine inlet and a substantially stoichiometric air fuel ratio in the combustion chamber. Water injection under these circumstances will be referred to as maximum water injection.

Accordingly the invention provides a gas turbine power plant utilising solid water-being fuel comprising a fuel drier to which hot compressed air and said fuel are supplied and in which at least part of the water content of the fuel is evaporated, a combustion chamber receiving said evaporated water content and solid fuel from the drier and a turbine receiving the combustion products and evaporated water content from the combustion chamber.

Preferably the evaporated water content is separated from the solid fuel and is passed through a heat exchanger in which it is heated by the turbine exhaust gases.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing, which is a diagrammatic layout of a gas turbine power plant for driving an alternator.

(Cl. Gil-39.46)

The plant comprises a compressor I connected by a shaft 2 to a turbine 3 which drives it.' The compressor I delivers hot compressed air through a duct to a fuel drier 5 to which is also delivered water-bearing fuel through an inlet E. y The heat of the compressed air serves to evaporate some` or all of the water content of the fuel and the resulting steam together with the air and solid content of the fuel is passed to a separator 1.

Here the solid fuel is separated out and led dithe exhaust gases before being passed to combus- 4 tion chamber 4. The combustion gases pass to turbine 3 which drives alternator 9 and the exhaust gases are discharged through the hot side of heat exchanger 8 to heat the air and steam as already described.

As large a proportion as possible of the air and steam should pass through the heat exchanger, rather than direct to the combustion chamber, so as to obtain the greatest advantage from the heat of the exhaust gases.

The feature of heating the evaporated water content by heat exchange with the turbine exhaust gases forms the subject of co-pending United States Patent Application Serial No. 245,946, led September 10, 1951, in the name of Campbell H. Secord.

It will be appreciated that the greater the moisture content of the fuel, the greater will become the quantity of air required to evaporate it and the greatest possible moisture content which this cycle will deal with efliciently is one which produces saturation of the compressed air at the inlet to the cold side of the heat exchanger 8, that is, the temperature at this point corresponds to the dewpoint. This gives the maximum temperature difference between the hot and cold sides of the heat exchanger 8.

Thus this cycle is only suitable for comparatively low moisture contents, up to about per cent in the drier, and this moisture content will require air in excess of that required for complete combustion of the order of 400 per cent. Larger moisture contents cannot be dealt with without a loss in efficiency. If desired, the incoming fuel to the drier can be pre-heated and partially dried by means of the exhaust gases after they leave the heat exchanger 8, for example, in the manner described in said co-pending United States Application Serial No. 103,993. The

of the Water content of the fuel in the drier II,

and the resultant steam, the hot 1gasesand ythe solid fuel are all led to the separator 'YI-3. :Here the gaseous and solid constituents are separated, the partly dried and preheated soli'dfueVWith its remaining Water content/being*suppliedto inlet 6 of the drier 5, and thesteamfandexhau'st gases being discharged at I4. This would make it possible to use raw fuel having-'a greater-moisture content than would otherwise be the case.

In the ideal case the various components 'of the plant will be designed for a particular 'set of conditions of air now, fuel supply, and lmoisture content of the fuel. In practice it may be necessary to introduce further controls, for instance, 'additional Water might have Itobe lintroduced intothe systemthrough inlet I5 betweenV the outlet of separator V'I and thelinlet to the'cold side of heat exchanger YB'to reduce'the temperature of the 'gases at the turbine and atthe 'same time to supplement the mass 4flow offg'ases through the cold side of theheat exchanger '8 n`the event of the moisture arising from 'the fuel being temporarily insui'iicie'nt.

I'claim:

l. Agas'turbine po'wrplant for utilizing solid waterbea'ring fuel comprising a source f hot compressed air; a drier having an inlet for Asaid fuel'andan outlet; means for supplying said hot Y having an inlet connected to the drier outlet, a first outlet for the solid fuel and a second outlet for`thefseparated air SAan'irl"Water montent; a combustion chamber having 'l an inlety connected to the rst outlet of the separator and an out- Aletfor combustion gases; a turbine having an `inlet connected -to the combustion chamber out- 'let-a'n'da'niitletr exhaust gases; and a heat exchanger f vvhich the cold side has an inlet connected -to the 1second outlet of the separatcrjaiidan-outlt1connected to deliver said air van'derapo'rateduralter content to the combustion chamber, "and the lhot side has an inlet connected -to the turbine outlet, and an exhaust outlet.

lZPlanteacording to claim 1 comprising an airi'compressor constituting said source of hot compressed air.

References Cited in the le 0f this vpatent 'UNITED-STATES PATENTS Number Name Date 1,197,456 Dinsmor'e Sept.'5, 1916 1,809,819 Caller June 16,3'1931 2,032,402 -Colby et4 al. Man-"3, 1'93'6 2,066,418 lOM2tl. Jan. A5, 1937 2,148,447 Dundas Iet a1 -Feb.l28,`1f939 2,171,535 Berge?, 'al Septf5, 1939 FOREIGN PATENTS Number Country 4'Date n 418,329 Great Britain Aug. 24,1904 '166,517 `Great Britain -..W-Sept. '7, 1922 OTHER *REFERENCES ",Engineerin'g,"-v vol-No.,169issue,No.74400QMay 26, 1950,'page 608. 

1. A GAS TURBINE POWER PLANT FOR UTILIZING SOLID WATER-BEARING FUEL COMPRISING A SOURCE OF HOT COMPRESSED AIR; A DRIER HAVING AN INLET FOR SAID FUEL AND AN OUTLET; MEANS FOR SUPPLYING SAID HOT COMPRESSED AIR TO THE DRIER TO EVAPORATE AT LEAST PART OF THE WATER CONTENT OF THE FUEL; A SEPARATOR FOR SEPARATING AT LEAST PART OF SAID AIR AND EVAPORATED WATER CONTENT FROM THE SOLID FUEL, HAVING AN INLET CONNECTED TO THE DRIER OUTLET, A FIRST OUTLET FOR THE SOLID DUEL AND A SECOND OUTLET FOR THE SEPARATED AIR AND WATER CONTENT; A COMBUSTION CHAMBER HAVING AN INLET CONNECTED TO THE FIRST OUTLET OF THE SEPARATOR AND AN OUTLET FOR COMBUSTION GASES; A TURBINE HAVING AN
 2. PLANT ACCORDING TO CLAIM 1 COMPRISING AN AIR COMPRESSOR CONSTITUTING SAID SOURCE OF HOT COMPRESSED AIR. 